Bird Boxes

Bird BoxBird Box

There is no standard design for a nestbox and one can be made from a large variety of materials. However, there are one or two points that should be noted. Boxes should be sited so that they are not prone to attack by predators and as most hole nesting species fly directly to the nest there should be a clear flight line to the box unobscured by vegetation or other obstruction.

Do not buy/build a box with a peg under the entrance hole to act as a perch, as it is unnecessary and provides a foothold for predators. Woodpeckers and grey squirrels can be a problem in some areas and will happily enlarge the hole or make a hole in the side of the box. The only way to protect against this is to cut up a large baked bean tin, coffee tin or similar and tack it to the sides and front of the box.

Buying a Bird Box

An excellent selection of bird boxes, as well as bird feeders and bird food, can be obtained from Vine House Farm. Vine House Farm, support the Wildlife Trust with a percentage of their sales so purchasing their products helps conservation in Birmingham and the black Country.

Making your own

Boxes can be made from most sorts of timber but do not use manufactured products such as plywood (unless it is resin-bonded marine ply), chipboard or MDF as they will not stand up to the weather. Treat the outside of the box with a wood preservative for added protection against the elements but do not treat the inside. A piece of roofing felt could be fixed to the roof for added protection.
As an aside, you will stand more chance of attracting birds to use the nestboxes you erect if you plant a few native plant species to attract insects and do not use pesticides in the garden. The birds need those insects to provide food for their young and chemicals are not good for humans either.
Not all birds are hole nesters, so if possible grow a variety of trees or shrubs to provide 
nest sites for blackbirds, thrushes and dunnocks to name but a few. Many garden hedges have been removed over recent years so nest sites are getting few and far between in some areas.

Siting

Most boxes are satisfactorily placed at head height but for woodpeckers get them as high in the tree as possible. Marsh tits on the other hand prefer boxes to be placed nearer the ground.
Birds will not generally use boxes that face due south as they are exposed to direct sunlight from dawn to dusk so boxes facing almost any other direction will be fine. Even a box facing north should be fine and not subject to extreme cold from northerly winds during the breeding season.
Try not to nail boxes to trees. Instead, fasten a batten across the back of the box protruding three or four inches each side and use strong polypropylene baler twine or fencing wire looped around the tree and tied to the batten to secure. The weight of the box and roughness of the tree bark should be sufficient to hold the box in place.

Many birds are territorial so placing boxes too close to each other can cause problems although sparrows are happy nesting as a community. Also bear in mind that the young of all garden birds are fed on insects – even the seed eaters like finches – therefore a garden can only support a limited number of bird families depending on the availability of insect food in the Spring/early Summer. Do not, therefore, put up too many boxes.
Do NOT place a nest box close to a bird table or feeding area, you would not want your bedroom next to a fast food takeaway and birds are no different.
Whilst nest boxes shouldn’t be placed near feeders or bird tables it is important to remember that adult birds and their chicks will require a good supply of food for successful nesting so please consider supplying supplementary foods and ensure that your garden has a wide range of trees, flowers, shrubs and other plants to provide as much natural food as possible.

Cleaning

After the end of each breeding season all nestboxes should be cleaned out, preferably in October or November. Take the box down, remove the lid and clean out all the old nest material (a good place to do this is over the compost heap). As birds have parasites clean the box well. Do not use any cleaning products. Instead scald the inside of the box with boiling water. This will remove any parasite left in the box. Put the box back up as soon as you have cleaned it as it may be used by birds over the winter as a roosting site.

Open fronted boxes

These are suitable for Robins if mounted low down – between one and two feet from the ground. They can be protected by rolling chicken wire into a ball and stapling over the front of the box. It looks a bit funny but robins can get through the holes, where squirrels, crows, cats and jays cannot. It must balloon out from the front of the box and not be nailed flat across the opening. Can be mounted behind ivy or better still a prickly shrub as added protection.
These mounted 10 feet or more up can be used by spotted flycatchers – most useful when attached to the blank wall of a house or other building. Again, use a wire mesh balloon.

Hole Sizes

Blue Tit 25mm Marsh Tit 25mm
Coal Tit 25mm Nuthatch 32mm
Great Tit 28mm Tree Sparrow 32mm
Pied Flycatcher (not a regular nester in city areas) 28mm

Woodpecker Boxes

Use a tall version of standard hole box approx. 450mm tall, 180mm square with an entrance hole of 60mm for green woodpecker or 400mm tall, 140mm square with an entrance hole of 50mm for great spotted. Fill with balsa wood or expanded polystyrene foam and start a small excavation about 20mm deep. If used, the foam/balsa will need replacing for the following season so ensure you have a removable lid to the box.
If you are not able to drill a round hole of such a size, a square one will do and this can be made by drilling four corner pilot holes and connecting them with a coping saw or similar. You could try a standard 28mm hole box filled with foam for lesser spotted woodpecker or willow tit.

Owls

Require special boxes – see drawings of chimney boxes suitable for tawny and little owls. Barn owl boxes are best left to specialists as they usually need careful site selection and placing in barns or other outbuildings.

Other Species

Boxes can be used for many species of birds including some species of duck.
Bat boxes look similar to bird boxes, but constructed rather differently – contact us for details.
It is also possible to create nesting or hibernating boxes for other creatures such as hedgehogs and some insects.